• 방송공학회논문지
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• 제16권6호
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• pp.962-968
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• 2011

기존의 무손실 압축은 일반적으로 채널간의 상관관계를 고려하지 않고 각각의 채널을 따로 압축하였다. 채널 간 상관관계를 이용하는 경우도 있으나 이들은 위성/항공 영상과 같은 경우에 제한된 것으로서 일반적인 이미지에 대해서는 만족할만한 성능을 얻지 못하였다. 본 논문에서는 컬러 이미지가 갖는 채널 간의 상관관계를 이용하여 무손실 압축의 성능을 향상시키는 방법을 제안하였다. 제안된 방법에서는 채널 간 상관관계를 표현할 수 있도록 하기 위하여, 비대칭 샘플링을 통해 주어진 영상의 모자이크 이미지를 구성하여 압축을 수행하였고, 압축된 모자이크 이미지의 정보를 이용해서 샘플링되지 않은 나머지 이미지를 예측하여 압축할 정보의 양을 감소시켰다. 제안된 방법은 압축 성능을 평가하는데 일반적으로 사용되는 데이터들에 대해서 채널 간 상관관계를 이용하지 않는 방법에 대해 35%, 채널 간 상관관계를 이용한 기존 방법에 대해 10%의 성능 개선을 보인다.

• 방송공학회논문지
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• 제6권2호
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• pp.177-186
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• 2001

워터마크란 저작권 보호를 위해 영상과 같은 멀티미디어에 심어두는 보이지 않는 신호를 말한다. 많은 경우에 워터마크 검출기법은 상관성을 구한 후, 그 값을 정해진 임계값과 비교하는 과정으로 이루어지는데 상관성을 구할 매 원영상의 사용 유무에 따라 2가지 부류로 나누어진다. Typel검출기는 원영상(original image)과 테스트할 입력영상과의 차신호를 상관기의 입력으로 사용 하는 경우이고, Type2검출기는 입력영상을 직접 상관기의 입력으로 사용하는 경우이다. Typel검출기는 올바른 저작권을 증명하 는데 어려움을 가진다. 반면. Type2 검출기는Typel검출기와 비교할 때, 올바른 저작권 증명에 있어서는 유리하지만 Typel검출기 가 가지지 않은 문제점을 안고 있다. 그 문제점은 워터마크와 워터마킹할 원영상 사이의 상관성이 워터마크의 에너지로 정규화할 때 그 값이 무시할 수 없을 정도로 크다는 점이다. 따라서 본 논문에서는 그 상관성이 워터마크 검출의 성능에 미치는 영향을 분석하면서 그 영향을 최소화하는 새로운 기법을 제안하고 제안된 기법의 성능을 분석한다.

• 대한간호학회지
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• 제33권3호
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• pp.331-338
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• 2003

Purpose: The purpose of this study was to investigate the relationships among variables of body image, self-esteem and depression in college female students according to the normal and overweight. Method: The subjects of this study consisted of 245 college female students. The data was collected through personal interviews using questionnaires from May to June of 2001. The data was analyzed by the SPSS computer program, and it included descriptive statistics, x$^2$-test, t-test and the pearson correlation coefficient. Result: Demographics provided a significant difference in grade, household income, weight control experience. There was a perceived health status difference, according to the normal and overweight subjects. There was a significant difference in body image, self-esteem and depression between the two groups. There was a significant positive correlation between body image and self-esteem, and negative correlation between body image and depression, and self-esteem and depression in college female students. Conclusion: The Findings of this study give useful information to construct further studies in intervention program relating overweight control for college female students.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2003년도 ISIS 2003
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• pp.563-566
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• 2003

Quality measures play an important role in the field of image processing. Such measures are commonly used to assess the performance of different algorithms that are designed to perform a specific image processing task. In this paper we propose two novel measures for image quality assessment based on the notion of correlation between fuzzy sets. Two different definitions fur the correlation between fuzzy sets have been used. In order to calculate the proposed quality measures two approaches were evaluated, one with direct application of the measures to the image′s pixels and the other using the fuzzy set corresponding to the normalized histogram of the image. A comparative study of the proposed measures is performed by investigating their behavior using images with different types of distortions, such as impulsive "salt at pepper" noise, additive white Gaussian noise, multiplicative speckle noise, blurring, gamma distortion, and JPEG compression.

• International journal of advanced smart convergence
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• 제1권1호
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• pp.6-13
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• 2012

An improved algorithm for image quality assessment is presented. First a simple model of human visual system, consisting of a nonlinear function and a 2-D filter, processes the input images. This filter has one user-defined parameter, whose value depends on the reference image. This way the algorithm can adapt to different scenarios. In the next step the average value of locally computed correlation coefficients between the two processed images is found. This criterion is closely related to the way in which human observer assesses image quality. Finally, image quality measure is computed as the average value of locally computed correlation coefficients, adjusted by the average correlation coefficient between the reference and error images. By this approach the proposed measure differentiates between the random and signal dependant distortions, which have different effects on human observer. Performance of the proposed quality measure is illustrated by examples involving images with different types of degradation.

• 한국통신학회논문지
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• 제22권2호
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• pp.392-400
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• 1997

In this paper we porposed WCHF-fSDF filter to obtain a roration and scale-invariant correlation output. WCHF-fSDF filter is synthesized by each single CHF exttracted from scale-changed and wavelet tranformed imagesfor a refereence image as tranining images. The wavelet transform is defined as the correlation of an input image with a wavelet function. Therefore two 4f optical correlation systems are needed for pattern recognition using wavelet transform. We here include the wavelet function for the input image in the process of the proposed filter design and substitute the two 4f optical correlation system with a single 4f optical correlation system. The Performances of the proposed filter are compared with conventional CHF-SDF, POCHF-SDF filters through the computer simulation. The results of computer simulation show that the proposed filter has the rotation and scale-invariant correlation output and it has better performances than thoseof the conventioanl filters.

• Journal of the Optical Society of Korea
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• 제19권3호
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• pp.241-247
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• 2015

The double-random phase encryption (DRPE) algorithm is a robust technique for image encryption, due to its high speed and encoding a primary image to stationary white noise. Recently it was reported that DRPE in the Fresnel domain can achieve a better avalanche effect than that in Fourier domain, which means DRPE in the Fresnel domain is much safer, to some extent. Consequently, a method based on DRPE in the Fresnel domain would be a good choice. In this paper we present an image-authentication method which uses only partial phase information from a double-random-phase-encrypted image in the Fresnel domain. In this method, only part of the phase information of an image encrypted with DRPE in the Fresnel domain needs to be kept, while other information like amplitude values can be eliminated. Then, with the correct phase keys (we do not consider wavelength and distance as keys here) and a nonlinear correlation algorithm, the encrypted image can be authenticated. Experimental results demonstrate that the encrypted images can be successfully authenticated with this partial phase plus nonlinear correlation technique.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 신호처리소사이어티 추계학술대회 논문집
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• pp.485-488
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• 2003

A conventional correlation target tracker is analysed with a simple mathematical approach. And, we will propose a correlation measure with selective attentional property in order to overcome the false-peak problem of the conventional methods. Various experimental results show that the proposed correlation measure is able to reduce considerably the probability of false-peaks degraded by the correlation between background images of a reference block and a distorted and noisy sensor input image.

• 제어로봇시스템학회논문지
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• 제6권5호
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• pp.390-395
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• 2000

We present a fingerprint identification algorithm using the wavelet transform and correlation. The wavelet transform is used because of its simple operation to extract fingerprint minutiaes features for fingerprint classification. We perform the rowwise 1-D wavelet transform for a $256\times256$ fingerprint image to get a $1\times256$ column vector using the Haar wavelet and repeat 1-D wavelet transform for a 1$\times$256 column vector to get a $1\times4$ feature vector. Using PNN(Probabilistic Neural Network), we select the possible candidates from the stored feature vectors for fingerprint images. For those candidates, we compute the correlation between the input binary image and the target binary image to find the most similar fingerprint image. The proposed algorithm may be the key to a low cost fingerprint identification system that can be operated on a small computer because it does not need a large memory size and much computation.

• Journal of the Optical Society of Korea
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• 제17권5호
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• pp.399-404
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• 2013

This article proposes a digital image correlation (DIC) strain measurement method based on a finite element (FE) algorithm. A two-step digital image correlation is presented. In the first step, the gradient-based subpixels technique is used to search the displacements of a region of interest of the specimen, and then the strain fields are obtained by utilizing the finite element method in the second step. Both simulation and experiment processing, including tensile strain deformation, show that the proposed method can achieve nearly the same accuracy as the cubic spline interpolation method in most cases and higher accuracy in some cases, such as the simulations of uniaxial tension with and without noise. The results show that it also has a good noise-robustness. Finally, this method is used in the uniaxial tensile testing for Dahurian Larch wood specimens with or without a hole, and the obtained strain values are close to the results which were obtained from the strain gauge and the cubic spline interpolation method.